HEI Distributor Tach issues, Issue has been resolved

Yes, the original GM style "big cap" distributors ALL had a filter from GM so the tach would operate correctly. I had to get one for my F250 to straighten it out. It worked fine. What distributor do you have and what filter did you use? The GM number for the filter is 14020025. They all had it if they had the big cap HEI. Be advised, NO OTHER distributor is HEI unless it is the big cap unit and uses the GM module. They are only imitations using the HEI name, so that could be an issue.